Hello Leah,
I agree with Cowboy. Whenever we have a run of tachycardia or feel our heart rate change it will have a tendency to cause us to freeze. The what if's coming flooding into our mind.
If you were checked out 2 1/2 years ago you may want to visit with your physician again just for reassurance.
Keep on posting here and we will support you always. Hugs to you.
Kitt